Dressing apparatus



April 5, 1938. A. VUILLEUMIER 2,113,186

DRESSING APPARATUS Filed Oct. 5, 1934 s sneets-shet 1 ICIGZ/ Fig. 2

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DRES s ING( APPARATUS Filed Oct.' 5, 1934 3 Sheets-Sheet 2 FIG. 4 FIG 5 2 0 I26 IN VENTOR. HLBERT VUlLLEUM/ER, BY

H16 Tm? v Patented Apr. 5, 1938 DRESSING APPARATUS Albert Vuilleumier, Bristol, Conn., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application October 5,

12 Claims.

This invention relates to dressing apparatus for grinding wheels and the like and comprises all of the features of novelty herein disclosed. An object of the invention is to provide a dressing apparatus which will perform its work at less cost than heretofore, especially in respect to the cost of the dressing tool itself. Another object is to provide an improved automatic dressing apparatus for abrading tools. Another object is to provide improved means for feeding and controlling the movements of a dressing tool or the like.

To these ends and also to improve generally upon devices of this character, the invention consists in the various matters hereinafter described and claimed. In its broader aspects, the invention is not necessarily limited to the specific construction selected for illustrative purposes in the accompanying drawings in which 20 Fig. 1 is a front elevation of the apparatus, with parts of the supporting structure in section.

Fig. 2 is a detail front view of a portion of the apparatus to large scale.

Fig. 3 is a plan view with some parts in section.

Fig. 4 is a sectional view about on the line 4--4 of Fig. 3.

Fig. 5 is a horizontal sectional view about on the line 5--5 of Fig. 4.

Figs. 6 and '7 are detail views of friction braking discs.

Fig. 8 is a vertical sectional view of a portion of the apparatus, the section being taken at right angles to that of Fig. 4.

Fig. 9 is an elevation of the dressing wheel 35 holder, with a portion in section.

Fig. 10 is a diagram of electrical and fluid pressure connections.

'rst outlining the general operation of an embodiment selected merely for illustration, a grinding wheel G, with a cylindrical face or faces to be dressed, is rotated around its axis while a rotary dressing wheel D is reciprocated along an element of the cylinder, the rotation of the dress- I ing tool being produced by frictional contact with the grinding wheel but being retarded by a brake. As the dressing tool reciprocates, a ratchet wheel is intermittently turned to effect relative rotation of screw threaded members thereby slowly feeding the dressing wheel towards the grinding wheel.

The grinding wheel G is enclosed in a guard 10 having a portion slabbed off fiat to receive a guide plate l2 which is fastened by screws l4, there being interengaging shoulders at Hi to position the guide plate laterally. A slide [8 1934. Serial No. 747,085

reciprocates along the guide plate on a guide rail of inverted V-shape and on flat ways 22, a rear gib 24 being fastened to the guide plate by screws 26 and a front gib 28 being secured by screws '30. To protect the front ways 22 from dirt, a shield 5 32 is fastened by screws to the gib 28 and has a downturned lip 34 entering a groove in the slide. The slide has a tubular bearing extension or pro- J'ection 36 which projects downwardly through an elongated slot 38 in the guide plate I2 and through a registering slot 40 in the wheel guard [6. To exclude grit from working up to the ways through the slots, an elongated cover strip 42 is fitted around the extension 36 above the slot 38 and is arranged to slide along in a shouldered recess of the guide plate, the cover plate being made long enough to cover the slot in any position of the slide.

A cylinder 44 is formed integrally with or secured to the rear of the slide I8 to shift with the latter and contains a fixed piston 46 secured'to a hollow piston rod formed in two sections 48 abutting against a partition 50 fixed in the piston. Each section has longitudinal slits 52 registering with radial grooves 54 in the sides of the piston, thus to form ports connecting the interior of the cylinder with the interior of the piston rod sections. The sections project through cylinder} heads 56 having packing glands 58 and their remote ends are secured in bracket arms 60 by set screws 62. g The bracket arms project forwardly and upwardly from brackets 64 secured to lugs 66 on the ends of the guide plate I2.

Pipes 68 and 10 are connected to the piston rod sections and to a reversing valve 12 (Fig. 10) having a piston. rod 14 with a pair of spaced pistons 16. Pressure fluid enters the valve through a supply pipe [8 and exhaust fluid leaves the valve alternately through the exhaust pipes and 82. Solenoids 84 and have their plungers connected to the piston rod 14 to shift the latter under control of switches 88 and 90 which are contained (Fig. 1) in switch boxes 92 fastened to the ends of the brackets 64. To shift the switches alternately and automatically, the reciprocating cylinder 44 carries adjustable headed screws 94 arrangedto engage pins 96 slidably supported by the brackets 64 and suitably connected to the switches. One of the pins 96 slides in a threaded bushing 98 as indicated at the right of Fig. 1, the bushing forming a stop for the headed screw 94. Both Fig. l and Fig. 10 show the cylinder at its extremity of movement to the right with the switch 88 closed, thus energizing the solenoid 84 andshifting the valve to a position in which pressure fluid will pass from the valve to the pipe 68 and then to the left end of the main cylinder to shift the cylinder to the left. This action will in turn close the switch 90, energize solenoid 86, and reverse the valve. Pressure fluid will then go from the valve through the pipe 10 to return the cylinder, etc., so that the reciprocating cylinder controls its own reversal.

The dressing wheel D is rotatably mounted (as will appear) in a hollow carrier or quill I00 which v is slidable up and down in the slide I8 and'its bearing extension 36, thus to feed the dressing wheel downwardly towards the grinding wheel. The quill has a keyway I02 engaged by a key I04 (Fig. 8) which is fastened in agroove of the slide I8 by screws I06. This construction prevents rotation of the quill but allows downward feeding. The quill is threaded externally throughout its upper portion and engages at I08 with internal threads at the upper portion of a sleeve I I0 which is rotatably supported and centered on the slide I6 by an annular shoulder or lip II2. A bridge .or yoke II4 (Fig. 1) has vertical legs fastened by bolts H6 to lugs I I8 on the slide I8, thus to leave a space where a ratchet I20 on the sleeve IIO will be exposed. A collar I22 is secured by a set screw I24 (Fig. 4) to the rotary sleeve H0 in a position spaced above the bridge II4. A dog carrying hub I26 is journalled for turning movement on the sleeve below the collar and is supported on the bridge II4. An arm I28 projects rearwardly from the hub in a position to engage an abutment screw I30 (Fig. 3) which is adjustably secured by a nut in a bracket arm I32, the contact of the arm I28 with the screw giving the hub a partial turning movement whenever the slide I8 reaches the right hand limit of movement. The amount of turning movement is controlled by adjusting the position of the abutment screw I36. Another arm I34 projects forwardly and downwardly from the hub and has a boss in which a ratchet dog I36 is slidably mounted. A leaf spring I38 fastened by a screw to the hub I26 extends downwardly back of a shoulder on the dog to urge the latter against the ratchet teeth. The dog can be manually retract ed from the ratchet by a hand wheel I42 and can then be locked out by turning its cross pin I44 crosswise of a vertical notch which it normally engages.

A coil spring I46 (Figs. 3 and 5) is secured at one end to a pin I48 on the hub I26 while its other end is anchored to a pin I50 on the bridge II4, thus to always move the hub clockwise when it has been moved counterclockwise by engagement of the arm I28 and the abutment screw I30. The ratchet dog I36 is of course oscillated with the hub but the rotary sleeve I I0 is held from retrograde movement by a detent dog I52 which is slidably mounted in the bridge and urged against the ratchet I20 by a leaf spring I54. The dog has a hand wheel I56 and a cross pin I58 so that it can be manually retracted and locked as in the case of the dog I36. The two dogs are thus locked out when a down feed of the quill I00 has been completed and it is desired to elevate it to starting position. Fig. 4 shows the quill near its lower limit of movement. As a limit to the action of the coil spring I46 in turning back the hub I26, a stop pin I60 projects from the hub in a position to engage the screw which fastens the leafspring I54 to the bridge.

At the lower end of the quill I00 in a recess thereof is a double row ball bearing I62 having its outer race ring clamped by an end cap I64. Near the upper end of the quill is a single row ball bearing I66 whose outer race ring has a sliding fit in the quill. The two inner race rings are secured to a hollow rotary spindle I68, being spaced apart by a spacing and braking sleeve I10 which is keyed near its upper end to the spindle. The inner race rings and the spacing sleeve are clamped together endwise as a unit by nuts I12 threaded on the upper end of the hollow spindle, the lower inner race ring abutting against a shoulder on the spindle.

There are internal keyways I14 near the upper end of the quill into which project lugs I16 on friction discs I18 surrounding the spindle and clearing the latter. The discs I18 alternate with friction discs I which clear the quill but have lugs I82 projecting into keyways I84 in the sleeve I10 above a supporting flange I86. On the uppermost disc I18 is supported a weight I30 in the formof a ring. This weight is so selected as to give the desired amount of braking friction between the discs so that the rotation of the spindle I68 will be retarded, thus causing the grinding wheel and the dressing wheel to have diiferent speeds when the former drives the latter by frictional contact. As shown in Fig. l, the quill I00 is at a small angle to the plane of the end face of the grinding wheel G, or, otherwise stated, the

.axis of the dressing wheel is a little out of a line normal to the grinding wheel, so that the grinding wheel meets the dressing wheel on one side only of the axis of the dressing wheel. The ressing wheel has an end face that is in the surface of a shallow cone and this conical surface has a line of contact with an element of the cylindrical grinding wheel. The frictional engagement of these parts causes the dressing wheel to be driven at a speed determined by the weight I 88, other factors remaining constant.

A chuck plate I at the lower end of the hollow spindle I68 has an internal conical face to wedge with a similar face on a circular holder I92 which has radial slits I04 to make the holder expansible and contractible, thus to grip a ring I96 of lead or the like which is molded to the dressing wheel D. The radial slits extend up into a hollow projection or stud I96 of the holder and this'stud is keyed to the chuck spindle by a pin 200. The upper end of the stud is threaded as at 202 to engage threads on the lower end of a draw rod 204 having a socketed head 206 engaging the upper end face of the spindle. By turning the draw rod, the holder is drawn upwardly into the chuck plate and the conical faces con tract the holder to grip the dressing wheel.

In operation, whenever it is desired to dress off the grinding wheel G, the dressing wheel D is brought down to the grinding wheel by turning the sleeve I I0, the ratchet dogs being temporarily retracted. The pressure fluid for the reversing valve 12 is then set in operation and the electric current turned on. The main slide I8 carrying the quill I 00 then reciprocates automatically as described above, carrying the dressing wheel D along the grinding wheel G. Contact of the rotating grinding wheel with the rotary dressing wheel frictionally drives the latter but the speed of the latter is retarded by the brake so that surface speeds are different and cutting will occur. Wheel D is preferably of softer abrasive than wheel G. Whenever the slide reaches the end of its stroke in one direction, the arm I28 engages the abutment screw I30, and the hub I26 carrying the ratchet feed dog I36 is oscillated through a small angle. This action slowly turns the threaded sleeve H with respect to the threaded quill and such intermittent down feed is continued until the surface of the grinding wheel is true. The dressing wheel and the quill are then raised from the grinding wheel by turning the threaded sleeve I ill in the opposite direction while the ratchet dogs are again temporarily retracted.

I claim:

1. In apparatus of the character described, a dressing wheel having a spindle, a carrier rotatably supporting the spindle, means for frictionally driving the dressing wheel, co-operating friction discs between the spindle and thevcarrier, and a weight for holding said discs in engagement.

2. In apparatus of the character described, a dressing wheel having a spindle, means for frictionally driving the dressing wheel, a sleeve keyed to the spindle, brake discs keyed to the sleeve, a quill rotatably supporting the spindle, brake discs keyed to the quill, and means for urging the brake discs together.

3. In apparatus of the character described, a Wheel guard having a slot, a guide plate on the wheel guard and having a slot, a slide movable on the guide plate and having a projection extending through said slots, a dressing tool shiftable with the slide and having a mounting in the slide and its projection, and an elongated cover plate secured to the slide around the projection and closing the slots.

4. In apparatus of the character described, a wheel guard having a slot, a slide shiftable lengthwise of the slot and having a tubular projection, a sleeve extending through the slide and its projection, a dressing tool carried by the sleeve, and an elongated cover plate secured around said slide projection and closing the slot.

5. In apparatus of the character described, an abrading wheel, a slide shiftable with respect to the wheel, a carrier sleeve shiftable endwise inthe slide, a bridge carried by the slide, a rotary member supported by the slide and having threaded engagement with the carrier sleeve, a ratchet wheel secured to the rotary member, a dog carrying member supported on the bridge and having a dog engaging the ratchet wheel, and means for oscillating the dog carrying member to turn the rotary member for effecting endwise movement of the carrier sleeve.

6. In apparatus of the character described, an abrading wheel, a slide shiftable with respect to the wheel, a carrier sleeve shiftable endwise in the slide, a spindle inside the sleeve and journalled for rotation therein, a dressing wheel on the spindle, a rotary member supported by the slide and having threaded engagement with the carrier sleeve, a ratchet wheel secured to the rotary member, a hub journalled on the rotary member and having an actuating arm, the ratchet wheel and the hub surrounding the carrier sleeve in concentric relation thereto and the hub member surrounding the rotary member, a dog carried by the hub and engaging the ratchet wheel, and an abutment arranged to engage the arm of the hub upon the shifting of the slide.

7. In apparatus of the character described, an abrading wheel, a slide shiftable with respect to the wheel, a carrier sleeve shiftable endwise in the slide and towards the abrading wheel, a dressing wheel rotatably supported by the carrier sleeve and frictionally engaging the abrading wheel, brake members housed in the carrier sleeve and concentric: therewith for retarding rotation of the dressing wheel, a sleeve rotatably supported by the slide and having threaded engagement with the carrier sleeve, and means for causing the shifting movement of the slide to turn the rotatably supported sleeve to feed the dressing wheel in the direction of its axis of rotation.

8. In apparatus of the character described, an abrading wheel, a slide shiftable with respect to the wheel, a pair of sleeves, one of the sleeves being shiftable endwise through the slide and held from rotation, the other sleeve being rotatably mounted on the slide and held from endwise movement, the sleeves having portions in threaded engagement with one another, means for causing the shifting movement of the slide to turn the rotatable sleeve, a dressing tool having a spindle rotatably carried by the non-rotatable sleeve and shiftable therewith, the dressing tool having a surface for frictional driving engagement with the abrading wheel, and brake mechanism mounted Within the non-rotatable sleeve for retarding the rotation of the dressing tool.

9. In apparatus of the character described, an abrading wheel, a slide shiftable with respect to the wheel, a carrier sleeve extending through the slide and shiftable endwise therein, a spindle rotatable in the carrier sleeve, a dressing tool on the spindle for frictional driving engagement with the abrading wheel, brake mechanism mounted within the carrier sleeve and reacting with the spindle to diminish the speed of the dressing tool, a threaded sleeve rotatably supported on the slide and having its internal surface in threaded engagement with the carrier sleeve, and means for shifting the slide to turn the threaded sleeve.

10. In apparatus of the character described, an abrading wheel, a slide shiftable with respect to the wheel, a carrier sleeve extending through the slide and shiftable endwise therein, a spindle extending through the carrier sleeve and journalled for rotation therein, a dressing wheel on the spindle and frictionally engaging the abrading wheel, means for causing the shifting movement of the slide to effect endwise movement of the carrier sleeve, and braking means interposed between the carrier sleeve andthe spindle.

11. In apparatus of the character described, an abrading wheel, a slide shiftable with respect to the wheel, a carrier sleeve extending through the slide and shiftable endwise therein, a spindle journalled for rotation in the carrier sleeve,

a dressing wheel on the spindle and frictionally engaging the abrading wheel, means for causing the shifting movement of the slide to efiect endwise movement of the carrier sleeve, brake discs carried by the spindle and the carrier sleeve, and means for urging said brake discs into contact.

12. In apparatus of the character described, a carrier sleeve, a spindle journalled for rotation in the sleeve, a dressing wheel on the spindle and frictionally driven, brake members carried by the spindle and by the sleeve, and means for urging the brake members into contact to retard rotation of the dressing wheel.

ALBERT VUILLEUMIER. 

